As with many papers in the sciences, there are multiple authors who aren't physically close to each other. I was curious about the most efficient and simplest way to technically share the writing. On the more complicated side would be LaTeX and subsequently using subversion to merge all of the changes. Then there is google docs. Finally, there is the traditional write out edits on word and email the document with comments back and forth.
What works?
If your collaborator is not technically inclined, then there are a few possibilities:
As a practical remark for the two last: always keep track of the version, e.g. draft_20120424_prof.pdf, where you add both date of the last edit (not final5!) and name of the last editor. When exchanging things by e-mail it is easy to loose track which version is the most recent and in fact lost changes (often not knowing about that.)
Other possibilities, requiring some technical knowledge:
When it comes to Dropbox - it is a good stuff for sharing files for a project but NOT for making changes in files. First, you never know when the changes happen. Second, you don't know where the changes happen.
There is also an article on it: Research tips - Online collaborative writing.
See also a few questions:
If you're working with Word documents, Word 2007 included a very nifty merge changes feature. This online help document from microsoft.com details how it works, but doesn't really do the feature justice. See the following screenshot for an idea:
Briefly, you can click on "compare" (in ribbon, third from right), and it lets you choose two source documents. From there, it opens the very nice interface shown above, with the two source docs on the right, the merged doc in the middle, and the changes on the left (or bottom, you can hide it if you don't wan t it). You use it like any other "track changes"; just go through, change by change, using the "previous", "next", "accept", and "reject" buttons om the Changes section of the ribbon. When you're done just save the combined document, and you've got your merged doc.
I've used this a number of times, and it's a very useful feature. By far the best aspect of this is that it can be used with the technically incompetent. Just tell them, "take the document, make changes, I'll deal with it"; I've used this with my technologically challenged boss a number of times, and it's been a lifesaver. Given your situation, this may be your best bet.
It also depends on what should be the final format of your document. For instance, I write all my articles in Latex, and when collaborating with other researchers, I use BitBucket: I create a Latex repository, and give access rights to the other authors. One good aspect of BitBucket is that they have a special plan for academics, where you can get an unlimited number of collaborators for free. In order to avoid conflicts as much as possible, we usually decompose the main document in one file for each section, and we try to avoid working on the same section at the same time, but even if it happens, then it's usually possible to easily merge the different edits. One nice feature is the possibility to automatically receive notifications when one author commit her changes. Also, since anybody can create a BitBucket account, there isn't the problem of creating an account to an external collaborator on an internal server.
Of course, BitBucket is not the only possibility, and one could also use Git, or even Dropbox, although for the latter, I don't really like the lack of native versioning system.
On the other hand, if I don't work directly on a paper, but for instance on a draft for a project proposal, then I use Google Docs, because it's quite simple to do some collaborative editing.
We do token passing and some kind of method to exchange the files. I think this method was covered in the comments but let me elaborate it here. I'll use Word as an example, since chances are if you're doing manual token passing, it's because you haven't been able to convince anyone in your team to switch to LaTeX, and people who don't want to switch to LaTeX are probably the type who don't want to deal with version control.
The "shared folder" is the mechanism you use for sharing files. It could be a Dropbox folder, email, WebDAV, a remote directory on an SSH-accessible server, etc.
Locking: Person who starts with the file renames it so that their name is on the end. They send an email to the group saying, "I am locking Section 1." List the locks in the email.
Unlocking: This is a multi-step process.
a. If no one else unlocked a section before you unlocked, then you can rename the file to the current date and time, then put it in the shared folder.
b. If another collaborator unlocked a section before you unlocked, then you must take the latest version off of the shared folder, copy the section you were working on, and paste it into the latest version you just downloaded. Rename the just-edited file to the current date and time, then put it in the shared folder.
The reason you do it this way and not the other way (copying and pasting everyone else's sections into your document) is because doing so means you have to keep track of what everyone else did, whereas this way you only need to keep track of what you did.
That's basically it. The biggest problem is when someone's not paying attention and doesn't merge properly, or when two people try to lock something at the same time (since Email has a delay) but usually you'll have to have someone who knows the process keep an eye out for it.
